The invention relates to an adjustable quick-release buckle, particularly for masks or similar, of the type provided in combination with a strap.
At present, as disclosed for example in U.S. Pat. Nos. 4,607,398, 5,611,644, 5,555,671 and DE 195 20 981, particularly in diving masks, buckles of the type described hereinbefore are used, which allow the strap to be stretched to tighten the mask, by simply exerting a pulling action in that direction on the free ends of the strap, which project out of the buckle, whereas the strap is loosened by manually acting on the release means, which bring the retaining means to temporary disengagement from the strap.
These buckles have a member for returning the strap, which return member brings the strap into cooperation with one retaining tooth. The return member also acts as an abutment member cooperating with the retaining tooth. The tooth has an asymmetrical profile, i.e. is provided with guide slanted surfaces, which help the strap to slide in the tightening direction, preventing it therefrom in the opposite direction, while said tooth is provided at the free end of a wing which is mounted in such a way as to be able to swing about an axis in the middle of and substantially parallel to the projections on the strap. The wing is elastically and stably loaded by a spring in order to press the tooth against the strap, i.e. against the return member.
This construction, though rather effective and convenient as regards strap tightening, always requires a certain effort which, on use, may involve a possible displacement of the mask from its correct wearing position. However, on releasing the strap, for example to take off the mask, the above well-known construction is quite unsuitable, inconvenient and involves the use of both hands. In order to bring the tooth into disengagement from the toothed end of the strap, the wing must be pressed against the force of the elastic means. This wing is generally disposed parallel to the temple or to the nearby zone, so a certain pressure action is to be exerted against the temple. At the same time, it is necessary to act on the strap, to help or assist its sliding movement inside the buckle in the loosening direction.